The present invention generally relates to a color picture or video signal processing circuit employed in a magnetic recording/reproducing apparatus or the like. More particularly, the invention is concerned with a filter circuit for noise elimination or reduction, a circuit for generating a composite color picture (video) signal by adding or mixing together a separated luminance signal and a separated carrier chrominance signal by making use of the filter circuit and a luminance/chrominance signal separation circuit for extracting separately the luminance signal and the carrier chrominance signal from the composite color picture signal.
As an attempt for improving the quality of picture generated by magnetic picture recording/ reproducing apparatuses (hereinafter also referred to as VTR in abbreviation) for home use, there have been established standards which permit the recording band to be widened. By way of example, according to the S-VHS standards, frequency band is broadened to 5 MHz, as a result of which there arises a need for improving or enhancing the performance of a Y/C separation circuit for separating the picture or video signal into a luminance signal (Y) and a carrier chrominance signal (C). However, in the present state of the art, the degree of Y/C separation is at most on the order of 30 dB. Consequently, there exist inevitably vestigial carrier chrominance signal components in the luminance signal.
Heretofore, a comb line filter has been employed for eliminating the vestigial carrier chrominance signal components. An example of this technique is disclosed in JP-A-63-27188.
An example of the filter designed for filtering a signal by making use of a pattern thereof is disclosed in "IEEE Trans. on Consumer Electronics", Vol. CE-28, No. 3 (August, 1982), pp. 157-167.
Further, a luminance/carrier chrominance signal separating circuit for separating a luminance signal and a carrier chrominance signal from a color picture signal is disclosed in "IEEE Trans. on Consumer Electronics", Vol. CE-31, No. 3 (August, 1983, pp. 24054 and JP-A-1-108890.